Compact antenna systems are desirable for reasons such as portability, cost, and ease of manufacture, and are particularly well-suited for mobile, wireless devices. Interest in compact antenna systems has been further stimulated by the use of higher radio frequencies, for example UHF and higher, which allow for antenna lengths significantly less than 10 centimeters.
However, factors such as decreasing a size of portable devices, decreasing power availability, and increased bandwidth and data rate requirements, make it increasingly challenging to provide for adequate antennas embedded in wireless devices. Approaches such as antenna diversity and multi-input multi-output (MIMO) communications may be used to provide performance improvements in many situations; however, it is again difficult to provide multiple antennas with adequate isolation and/or envelope correlation coefficient in physically small wireless devices.
Various mobile wireless devices are available which include multiple antennas. However, such antennas generally come with limitations, and it remains difficult to provide an antenna or multi-antenna system which exhibits acceptable performance for a given application, for example as measured by factors such as gain, efficiency, bandwidth, q-factor, antenna isolation, and envelope correlation coefficient. In addition, it is desirable to provide antennas which satisfy regulatory requirements with regard to specific absorption rates (SAR), and which operate adequately when housed in close proximity with other electronic components of the mobile wireless device.
Therefore there is a need for a compact wireless device and multi-antenna system that is not subject to one or more limitations of the prior art.
This background information is provided for the purpose of making known information believed by the applicant to be of possible relevance to the present technology. No admission is necessarily intended, nor should be construed, that any of the preceding information constitutes prior art against the present technology.